Photodiodes sensitive to infrared light, particularly in the spectral region of wavelengths measuring about ten micrometers, have become increasingly important in recent years for both military and industrial uses. In the military they are used extensively in surveillance systems and homing type guidance systems. In industry they are used to observe and control products in extremely hot environments such as furnaces and anneling ovens. These devices are easily fabricated, but the processes used heretofore have not provided satisfactory yields.